Pallet with a base plate and legs of metal

ABSTRACT

A pallet includes a base plate of cantilever construction and legs of metal, particularly as an underframe for pallet containers for transporting and for storing liquids in an inner container of synthetic material standing on the base plate of the pallet, and an outer casing composed of a grid structure or sheet metal material attached to the base plate. The base plate and the legs of the pallet are manufactured as a single piece from a sheet metal plate as the initial material by deformation, particularly by deep-drawing and/or pressing or by hydroforming.

[0001] This application is a divisional of U.S. application Ser. No.09/638,092, filed Aug. 11, 2000.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a pallet with a base plate andlegs of metal, particularly as an underframe for pallet containers fortransporting and for storing liquids in an inner container of syntheticmaterial standing on the base plate of the pallet, and with an outercasing composed of a grid structure or sheet metal material attached tothe base plate.

[0004] 2. Description of the Related Art

[0005] In the past, metal pallets were manufactured as welded metalsection or metal pipe constructions or of deep-drawn components andmetal sections. As a rule, the welded metal constructions have a highweight and are very difficult and complicated to manufacture. Thelightweight constructions of deep-drawn components usually have a lowstructural strength and they are difficult to stack and to transport. Inmost lightweight constructions of deep-drawn components, the pallet legsare formed by cup-shaped deep-drawn components which are closed towardsthe outer side of the pallet. The strength of the pallet is ensuredprimarily by a closed basic pallet construction to which the pallet legsare welded. The connections of the pallet legs to the base plate of thepallet and to the outer casing of a grid structure or sheet metalmaterial in a pallet container equipped with an inner container ofsynthetic material are usually screw connections. This type ofconstruction does not make it possible to provide, or makes it difficultto provide, pallets of metal with skid rails because the pallet legs arenot constructed as structural supporting members. It is technically verydifficult to provide an improved connection of the pallet legs to thebase plate. In addition, assembled pallets are difficult to stack andtransport because they cannot be nested. Finally, a weight-saving basicpallet construction of synthetic material or wood has in the past notbeen manufactured for pallet containers because of the insufficientinherent stability of the pallet legs.

SUMMARY OF THE INVENTION

[0006] Therefore, it is the primary object of the present invention todevelop a metal pallet which has a high stability while having a lowweight, and which can be stacked in an optimum manner and makes itpossible to manufacture a wide variety of types of basic palletconstructions.

[0007] In accordance with the present invention, the base plate ofcantilever construction and the legs of the pallet are manufactured as asingle piece from a sheet metal plate as the initial material bydeformation, particularly by deep-drawing and/or pressing or byhydroforming.

[0008] The various features of novelty which characterize the inventionare pointed out with particularity in the claims annexed to and forminga part of the disclosure. For a better understanding of the invention,its operating advantages, specific objects attained by its use,reference should be had to the drawing and descriptive matter in whichthere are illustrated and described preferred embodiments of theinvention.

BRIEF DESCRIPTION OF THE DRAWING

[0009] In the drawing:

[0010]FIG. 1 is a perspective view of a pallet with partially open legsand a base frame;

[0011]FIG. 2 is a perspective view, corresponding to FIG. 1, showing thepallet without base frame;

[0012]FIG. 3 is a perspective view of a sheet metal plate used formanufacturing the pallet according to FIGS. 1 and 2;

[0013]FIG. 4 is a perspective view of a base plate with open legs for apallet;

[0014]FIG. 5 is a perspective view of a base plate of FIG. 4 whose legsare covered with cover plates;

[0015] FIGS. 6 to 8 are perspective views showing different embodimentsof sheet metal plates for manufacturing base plates with legs forpallets; and

[0016]FIG. 9 is a perspective view of a pallet with skid rails.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The principal components of the pallet 1 according to FIG. 1 arean upwardly arched base plate 2, four corner legs 3 to 6 and four middlelegs 7 to 10 of sheet steel and a base frame 11 made of steel pipe andattached to the corner legs and middle legs 3 to 10.

[0018] The base plate 2 of cantilever construction as well as the fourcorner legs 3 to 6 and the four middle legs 7 to 10 of the pallet 1,with base frame 11 according to FIG. 1 and without base frame accordingto FIG. 2, are deep-drawn as a single piece from a sheet metal plate 12shown in FIG. 3, wherein the cup-shaped four corner legs 3 to 6 and thethree middle legs 7 to 9 at the two longitudinal sides 2 a, 2 b and therear side 2 c of the base plate 2 are closed to the side and bottom andare open towards the top. The middle leg 10 at the front side 2 d of thebase plate 2 is open towards the top and towards the front.

[0019] The base plate 2 has four stiffening ribs 14 extending from thecorner legs 3 to 6 towards the central plate portion 13 and anadditional edge stiffening rib 18 which extends along the twolongitudinal sides 2 a, 2 b, the rear side 2 c and the front side 2 d ofthe base plate 2 and completely or partially through the corner andmiddle legs 3 to 10.

[0020] The base plate 2 of the pallets 1 according to FIGS. 1 and 2additionally has a bridge-like stiffening portion 19 formed of parallelstiffening ribs 20 in the base plate 2, wherein the stiffening ribs 20extend from the middle section 21 of the longitudinal side 2 a throughthe central plate portion 13 to the middle section 22 of the oppositelylocated longitudinal side 2 b of the base plate 2, and wherein themiddle legs 7, 9 are integrated in the bridge-like stiffening portion19.

[0021] The base plate 23 according to FIG. 4 which is deep-drawn from asheet metal plate 12 has open corner legs and middle legs 3 a-6 a, 7a-10 a which, as illustrated in FIG. 5, are covered by cover plates 24to 26.

[0022] The flat sheet metal plate 12 according to FIG. 3 which is usedfor deep-drawing the base plate 2 and the legs 3 to 10 for the pallets 1according to FIGS. 1 and 2 as a single piece has different platesections 27 to 29 with different thicknesses for obtaining differentstrength values and to adjust to the different load zones of the baseplate 2.

[0023] This optimization of the sheet metal structures, which is alsoknown under the term tailored blanking, is carried out in order toachieve a cost-saving production of the structural components whilesimultaneously improving the product. Sheet metal plates 12 withdifferent thickness sections for manufacturing base plates 2 with legs 3to 10 are produced by flexible rolling in which the adjustment of theroll gap during the rolling process is controlled in accordance with thedesired plate thicknesses.

[0024] Moreover, for manufacturing base plates 2 with legs 3 to 10 it isalso possible to use sheet metal plates 30 in accordance with FIG. 6which are composed of welded-together sheet metal sections 31 to 33 withdifferent thicknesses in accordance with the different load zones of thebase plates 2.

[0025] The sheet metal plates 30 can also be composed of welded-togethersheet metal sections 31 to 33 having different material compositionsdepending on the different load zones of the base plates 2.

[0026] The sheet metal plate 34 according to FIG. 7 used for thesingle-piece manufacture of base plates 2 with legs 3 to 10 as shown inFIGS. 1 and 2 is provided with pre-shaped stiffening ribs 20 of thebridge-like stiffening portion 19.

[0027] The sheet metal plate 35 according to FIG. 8 for manufacturingbase plates 2 with legs 3 to 10 is composed of a sheet metal section 36with the preshaped stiffening ribs 20 of the stiffening portion 19 andtwo flat sheet metal sections 37 which are welded together.

[0028] Without the base frame 11, the pallets 1 according to FIG. 2 canbe stacked in each other.

[0029] In the pallet 1 illustrated in FIG. 9, skid rails 38 of metal,synthetic material or wood are attached to the legs 3 to 10.

[0030] The pallet 1 with an upwardly arched base plate 2 is preferablyused as an underframe for pallet containers for transporting and storingliquids with an inner container of synthetic material placed on the baseplate and with an outer casing of a grid structure or sheet metalmaterial attached to the base plate and the legs, wherein the bottom ofthe inner container, constructed as a bottom for draining the liquid forcompletely emptying the pallet container, is adapted to the curvature ofthe base plate of the pallet.

[0031] Moreover, the pallet 1 can also be used with a flat base plate 2as a transport and storage pallet for goods of various types.

[0032] While specific embodiments of the invention have been shown anddescribed in detail to illustrate the inventive principles, it will beunderstood that the invention may be embodied otherwise withoutdeparting from such principles.

I claim:
 1. A method for manufacturing a pallet of a cantileverconstruction comprising a base plate and legs of metal as an underframefor pallet containers for transporting and storing liquids, wherein thepallet container comprises an inner container of synthetic materialresting on the base plate of the pallet and an outer casing of a gridstructure or sheet metal material attached to the base plate, the methodcomprising the step of: shaping the base plate and the legs of thepallet of a single piece of a sheet metal plate by a shaping processselected from deep-drawing and/or pressing and hydroforming.
 2. Themethod according to claim 1, wherein the step of shaping comprisesforming stiffening ribs in the base plate.
 3. The method according toclaim 2, wherein the step of shaping comprises forming additionalparallel stiffening ribs in the base plate to produce a bridge-likestiffening portion in the base plate, wherein the additional stiffeningribs extend from a middle section of a longitudinal or transverse sideof the base plate through a central plate portion and to a middlesection of an oppositely located longitudinal or transverse side of thebase plate.
 4. The method according to claim 3, wherein the step ofshaping comprises forming middle legs at the sides of the base plate soas to be integrated in the bridge-like stiffening portion of the baseplate.
 5. A sheet metal plate for manufacturing a pallet of a cantileverconstruction by shaping a base plate and legs of the pallet of a singlepiece sheet metal plate by a shaping process selected from deep-drawingand/or pressing and hydroforming, wherein the sheet metal plate hassections, having different thicknesses, different material compositions,or different thickness and different material compositions, forobtaining different strength values adapted to different load zones ofthe base plate.
 6. The sheet metal plate according to claim 5,comprising preshaped stiffening ribs.
 7. The sheet metal plate accordingto claim 5, wherein one of the sections is a plate section withpreshaped stiffening ribs and at least two of the sections areadditional flat plates welded to the plate section to form the singlepiece sheet metal plate.
 8. A sheet metal plate for manufacturing apallet of a cantilever construction by shaping a base plate and legs ofthe pallet of a single piece sheet metal plate by a shaping processselected from deep-drawing and/or pressing and hydroforming, wherein thesheet metal plate is comprised of sections, having differentthicknesses, different material compositions, or different thickness anddifferent material compositions, for obtaining different strength valuesadapted to different load zones of the base plate, wherein the sectionsare welded together to form the single piece sheet metal plate.
 9. Thesheet metal plate according to claim 8, wherein the single piece sheetmetal plate comprises preshaped stiffening ribs.
 10. The sheet metalplate according to claim 8, wherein one of the sections is a platesection with preshaped stiffening ribs and wherein at least two of thesections are additional flat plates welded to the plate section to formthe single piece sheet metal plate.